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Using cannabis while pregnant could potentially contribute to lower birth weights, childhood obesity and high blood sugar, according to a study out today in The Journal of Clinical Endocrinology and Metabolism.
As an increasing number of pregnant people report using cannabis, understanding how the substance could impact fetuses and children is paramount, Brianna F. Moore, lead author of the study, told Insider.
"Pregnant women are dealing with so much. I could see why they might think cannabis would be an alternative, like to an antidepressant they were told to get off of during pregnancy, or to treat some of the pregnancy-related symptoms. There's just not enough public-health messaging out there," Moore told Insider.
To study how cannabis affects fetuses and young children, Moore and her team in Colorado, where cannabis is legal for medical and adult use, recruited 103 women from the University of Colorado Hospital's outpatient obstetrics clinics. The women, who came from an ethnically and racially diverse candidate pool, were healthy with no underlying conditions and were only giving birth to one child.
When the participants were 17 weeks pregnant, the researchers analyzed their urine samples for cannabis exposure, and found 15% of the women had fetal cannabis exposure. They ran the same tests at 27 weeks and when the babies were born. Once the participants' children were about 5, the researchers measured their fat mass levels, BMI, and blood sugar levels.
They found that children who were born to women who used cannabis during pregnancy with more likely to have low birth weights. When these children came for their follow-ups years later, those whose mothers used weed during pregnancy were more likely to have high blood sugar and high adiposity, a measure of body fat which can contribute to obesity risk.
The researchers were unable to pinpoint the effects of specific cannabinoids, like CBD and THC, on pregnancy. Moore said it's a future area of research she wants to explore.
"I'm hoping by doing that, we'll be able to capture more and differentiate between the two [CBD and THC]. I think people really want to know if there's something they can safely use, and we just don't know," Moore said.
Other small and inconclusive studies have examined the risk of using cannabis while pregnant.
A November 2021 study found children who were exposed to cannabis in the womb are more likely to show high anxiety, aggression, and hyperactivity than those who weren't exposed, Insider previously reported.
Cannabis use during pregnancy could also potentially increase the risk of low birth weight and preterm delivery and autism in children.
Due to a lack of conclusive research, experts say pregnant people should stop using cannabis altogether.
In October 2019, the FDA issued a statement about the dangers of using CBD and THC, the two main chemical compounds in cannabis, while pregnant or breastfeeding.
"FDA strongly advises against the use of cannabidiol (CBD), tetrahydrocannabinol (THC), and marijuana in any form during pregnancy or while breastfeeding," the agency said in its statement.
